Abstract: Brake force proportioning system for a vehicle includes a two-way valve in the line between a diagonally connected front and rear wheel. A controller opens the valve continuously in a first region of brake pressure so that the brake force proportioning follows a fixed proportioning characteristic. Outside this region the valve is opened in pulses so that the proportioning follows an ideal characteristic curve. If the controller fails, a pressure limiting valve takes the place of the two-way valve and effects a pressure distribution according to a characteristic parallel to the fixed slope characteristic.